It is known to provide an aluminum foil between to polyethylene layers on one side of a cardboard layer in order to make the resulting laminate light-proof and oxygen-proof. Such an aluminum foil is very expensive and is only justified when the requirements with respect to imperviousness to light and oxygen are very strict. It is also known to manufacture a packing material for milk from colored polyethylene, which provides a relatively good imperviousness to light, but does not guarantee imperviousness to oxygen.